There has been disclosed a hydraulic pressure energy recovery apparatus which is installed on a construction machine such as a hydraulic excavator or the like and which includes a hydraulic motor that is operated when a return hydraulic fluid flowing out of a hydraulic actuator such as a hydraulic cylinder flows into the hydraulic motor, an electric generator that generates electric energy when the drive power from the hydraulic motor is applied to the electric generator, and a battery that stores electric energy generated by the electric generator (see, for example, Patent document 1).